docs: def pan_delta(self, d):
          """Pan the view by a given amount."""
          dx, dy = d
  
          pan_x, pan_y = self.pan
          zoom_x, zoom_y = self._zoom_aspect(self._zoom)
  
          self.pan = (pan_x + dx / zoom_x, pan_y + dy / zoom_y)
          self.update()